Is there an official limit on voltage drop/cable length in domestic circuits in the NEC?
In most European countries there is a hard 3% limit from the main panel to the end of each circuit. Most electricians have rules of thumb for common circuit and wire sizes (e.g. 1.5 mm2 at 16 amps = 17 m maximum length). Yesterday I started to wonder about the comparably large conductors used in US domestic circuits (for the same currents as in Europe) and ran a voltage drop calculation to see whether that might be one reason. Much to my surprise I found out that, assuming the European 3%, the maximum length of a #14 circuit on a 15-amp breaker would be 14 m (roughly 46 feet), which seems very short, if not impossible for larger homes, especially if the panel happened to be in the basement. Is this issue ever considered in domestic wiring in the US?
